圆回线和矩形回线源瞬变电磁响应差异性计算  

Response difference between circle and rectangular loop TEM

作　　者：薛俊杰[1] 周楠楠[2] 王贺元[1] 

机构地区：[1]辽宁工业大学理学院,辽宁锦州121001 [2]中国科学院地质与地球物理研究所矿产资源研究重点实验室,北京100029

出　　处：《物探与化探》2018年第1期178-184,共7页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(41474095;11572146);辽宁省教育厅科研基金项目(L2013248)

摘　　要：在回线源瞬变电磁发展的早期,往往使用圆回线产生的场来近似模拟多边形回线的场。为了对这种近似的影响进行分析,本文以矩形回线为例,对圆回线近似模拟多边形回线的误差进行计算。首先,根据给出的圆回线和矩形回线内外任一点的感生电动势新的计算方法,对两种回线装置内的感生电动势分布进行对比。研究结果表明:在扩散场早期,圆回线和矩形回线场的等值线分布形态存在较大的差别,而在扩散场中晚期,两种回线感生电动势相对误差较小。两种回线感生电动势相对误差的变化特征可以用感应电流烟圈扩散的理论进行解释。通过理论模型的分析可知,圆回线近似矩形回线会对浅层电性结构分析带来较大影响。In the earlier period of the development of loop source TEM, circular loop was commonly used to approximately simulate the rectangular loop. In order to study the effect of this approximate calculation, the authors analyzed the bias caused by the approximation of rectangular loop with circular loop in this paper. According to the induced electromotive force formula of circular loop and rectangular loop at arbitrary point inside or outside the loop, the response distribution of the two loops was investigated. The results demonstrate that, at the early stage of diffusive field, large difference is caused by the approximation, while at the late stage, relatively small difference is brought out, which can be explained by the theory of smoke ring. Theoretical modeling indicates that the simulation of rectangular loop by circular loop will bring about some errors and lower the detection precision.

关 键 词：圆回线 矩形回线 感生电动势 感应电流烟圈 浅层 

分 类 号：P631[天文地球—地质矿产勘探]